The present invention relates generally to communication networks, and more specifically, to a multiprotocol encapsulation system and method for protocols such as Fibre Channel, ESCON, Infiniband, or SONET over Ethernet for transport applications.
Wavelength Division Multiplexing (WDM) is an optical technology that couples many wavelengths in the same fiber, thus effectively increasing the aggregate bandwidth per fiber to the sum of the bit rates of each wavelength. Dense WDM (DWDM) is a technology with a larger (denser) number of wavelengths (e.g., >=40) coupled into a fiber than WDM. Systems may support, for example, 100 wavelengths per fiber, enabling a single fiber to carry several hundred gigabits of information. DWDM increases the capacity of embedded fiber by first assigning incoming optical signals to specific frequencies within a designated frequency band and then multiplexing the resulting signals out onto one fiber. DWDM combines multiple optical signals so that they can be amplified as a group and transported over a single fiber to increase capacity. Each signal can be at a different rate and in a different format. DWDM applications include ultra-high bandwidth long haul as well as ultra-high-speed metropolitan or inner city-networks, and at the edge of other networks such as SONET, Internet protocol (IP) and asynchronous transfer mode (ATM).
In conventional DWDM applications, many different protocols need to be aggregated into a single data channel to be transported over a wavelength. For example, a single 10 Gigabit DWDM channel can carry multiple lower-speed source application protocols such as ESCON (200 M), Fibre Channel (FC) (1.0625 G) or Gigabit Ethernet (GE) (1.25 G), and multiple channels of those protocols need to be converged to one transport interconnect signal, such as the 10 Gigabit Ethernet (IEEE 802.3.ae) or SONET (OC-48, OC-192), which are the most prominent choices for DWDM technology.
Since the DWDM protocol of either Gigabit Ethernet or SONET is different from the source application protocols, one way to converge the application protocols is to participate the protocol and terminate the application at the connecting node and regenerate the application protocol at the other end. This, however, involves complicated and expensive system designs. A more efficient method is to perform a transparent interconnect, so that the application protocol data is directly carried through Gigabit Ethernet. Conventional systems, however, do not provide for mapping of different protocols over common Ethernet transport. Conventional systems have begun to provide mapping of Ethernet, ESCON, and Fibre Channel protocols for transport over SONET. However this mapping requires a protocol such as the HDLC (High-level Data Link Control) [POS (Packet over SONET)] or the GFP (Generic Framing Procedure) for packet delineation. The HDLC packet delineation imposes a variable overhead. In the worst case, the overhead doubles the bandwidth required. The GFP packet delineation requires a complex variable length based Hunt procedure to maintain packet boundary alignment. The total overhead required to support packet delineation and multiplexing of multiple packet streams is higher than the method described here. In particular, with this added overhead, 10 Gb/s Ethernet cannot be carried in 10 Gb/s SONET (OC 192). In comparison, Ethernet employs identical packet delineation to that of ESCON and Fibre Channel that is based on explicit Start-of-Packet and End-of-Packet Link Control Characters or Words. This mapping is simple and has a fixed small overhead. The mapping permits 10 Gb/s Ethernet to be carried as a signal with its native coding.